1 files changed, 38 insertions, 19 deletions

diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index 440323a997c6..728f5029d533 100644
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c
@@ -118,6 +118,8 @@ collect_registered_events(struct tep_event *event, struct tep_record *record,
 	struct trace_instance *trace = context;
 	struct trace_seq *s = trace->seq;
 
+	trace->processed_events++;
+
 	if (!event->handler)
 		return 0;
 
@@ -127,6 +129,31 @@ collect_registered_events(struct tep_event *event, struct tep_record *record,
 }
 
 /*
+ * collect_missed_events - record number of missed events
+ *
+ * If rtla cannot keep up with events generated by tracer, events are going
+ * to fall out of the ring buffer.
+ * Collect how many events were missed so it can be reported to the user.
+ */
+static int
+collect_missed_events(struct tep_event *event, struct tep_record *record,
+		      int cpu, void *context)
+{
+	struct trace_instance *trace = context;
+
+	if (trace->missed_events == UINT64_MAX)
+		return 0;
+
+	if (record->missed_events > 0)
+		trace->missed_events += record->missed_events;
+	else
+		/* Events missed but no data on how many */
+		trace->missed_events = UINT64_MAX;
+
+	return 0;
+}
+
+/*
  * trace_instance_destroy - destroy and free a rtla trace instance
  */
 void trace_instance_destroy(struct trace_instance *trace)
@@ -181,6 +208,17 @@ int trace_instance_init(struct trace_instance *trace, char *tool_name)
 	 */
 	tracefs_trace_off(trace->inst);
 
+	/*
+	 * Collect the number of events missed due to tracefs buffer
+	 * overflow.
+	 */
+	trace->missed_events = 0;
+	tracefs_follow_missed_events(trace->inst,
+				     collect_missed_events,
+				     trace);
+
+	trace->processed_events = 0;
+
 	return 0;
 
 out_err:
@@ -530,25 +568,6 @@ void trace_events_destroy(struct trace_instance *instance,
 	trace_events_free(events);
 }
 
-int trace_is_off(struct trace_instance *tool, struct trace_instance *trace)
-{
-	/*
-	 * The tool instance is always present, it is the one used to collect
-	 * data.
-	 */
-	if (!tracefs_trace_is_on(tool->inst))
-		return 1;
-
-	/*
-	 * The trace instance is only enabled when -t is set. IOW, when the system
-	 * is tracing.
-	 */
-	if (trace && !tracefs_trace_is_on(trace->inst))
-		return 1;
-
-	return 0;
-}
-
 /*
  * trace_set_buffer_size - set the per-cpu tracing buffer size.
  */